With soundproofing underway and a study in hand saying those measures will all but ensure live music at Buffa’s falls within the city’s sound ordinance, the Esplanade Avenue bar is planning to return to a full schedule of performances next month after the expiration of a 60-day agreement it signed with a neighbor who sued over loud music at the venue. But that decision promises to set off another round in the legal fight between Buffa’s and Sydney Torres IV, the former president of SDT Waste and Debris Services, who said the bar must stick to a four-day music schedule, regardless of how much of its music is or is not leaking off the property and into his bedroom.Since heading off a lawsuit in August by agreeing to a reduced music schedule, Buffa’s has been working to make sure its music will not create problems, owner Chuck Rogers said. That included making renovations to the building, some of which already had been planned.“We have the right to exist as a business. We also have the responsibility to be neighborly,” Rogers said. “We can do both.”